Stem borers and red palm weevils are classified as economic pests because of their role in destroying the national economy of the afflicted countries. As an example, red palm weevils are considered to be the most serious blight, which threatens million of palm trees as well as coconut and ornamental palms in the gulf region and the whole world. At stake is the multi-million dollar date industry and the survival of historical icons.
Infestation was first discovered in the UAE in 1985, it was located in one of the farms. Soon after that, it spread to ten other firms. Nowadays, thousands of farms are estimated to have been infested by this weevil in the gulf and Arabian peninsula.
Such an exponential infection rate could, theoretically, blight the last remaining healthy palms in just a few years time. Red palm weevils are by no means limited to Arabia; they have already spread widely across Pakistan, India, Philippine, Iran and many other countries.
The seriousness of this problem attracted worldwide attention. Researches have been established and projects have been launched around the world to confront this winged plague. Arab governments as well as Arab Organization for Agricultural Development (AOAD), Islamic Development Bank (IDB) and International Fund for Agricultural Development (IFAD) fund-related projects and researches in the Arab countries.
The difficulty in controlling palm weevils is that they bore deep inside the palm trunk which made it hard for the insects to be got at with chemicals. Besides, early detection of infestation is difficult and treatment even in early stages may be too late to save the tree.
The symptoms of infestation vary, but commonly involve the followings: yellowness and wilt of palm leaves; fissures and burrows at the lower part of the trunk; affected palm attracts insects such as ants; beetles and worms, which feed on weevil's excreta, mixed with palm extraction. (A dark red stinky liquid found on the infested palm's stem).
Palm weevil is most active in a temperate weather and cold nights, during which weevils deposits their eggs into the fissures of a newly trimmed palms or around new shoots or inside the burrows made by other insects such as rhinoceros beetles.
Weevil's eggs are contained in a protective case or ootheca, which makes them immnune to the harmful effect of insecticides.
Later, eggs hatch into larvae known as grubs (grown grub is about 6 cm). The grub stage is the most destructive to the palm, since grubs feed entirely on palm tissue (trunk kernel). Grubs burrow inside the trunk, producing tunnels and fissures. As a result, palm extraction flows. Some of it feeds the grubs, the rest flows outside as a yellow clingy liquid, which turns after awhile into dark red. So, finding such substance on the palm stem is the first sign of infestation. Sometimes it is hard to observe the liquid, especially when the trunk is covered with shoots and dried fibers.
If not treated, grubs continue burrowing into the trunk, which spreads infestation. At the same time, the first infested site at the palm trnk still attracts insect females to deposit their eggs into it. So, at one instance of time, we find different phases of the insect in the same palm.
Grub reproduction can go on and on until a big hollow is made inside the trunk, causing it eventually to collapse and fall down, after which weevils, as all parasites do, start searching for another victim. According to some experts, each infected tree produces enough weevils to infect at least seven healthy new trees a year.
That briefly explains the seriousness and difficulty of controlling such a pest, which many experts like to call it palm AIDS or cancer.
Up until now, pest control is focused on traditional methods such as insecticides, pheromone traps, biological control, whereby special species of anti-insect worms are injected into the trunk of infected palm trees, etc. Despite all the efforts used, traditional methods proved to be not effective enough to eradicate the pests and prevent them from spreading to health plantations. Besides, they are associated with many side effects to humans and the environment.
Treating infested palm with this machine for just a few minutes will guarantee killing all weevils found on the palm in any of their phases.